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authorIra Weiny <ira.weiny@intel.com>2021-11-05 23:45:06 +0300
committerLinus Torvalds <torvalds@linux-foundation.org>2021-11-06 23:30:43 +0300
commitd2c20e51e3966bc668ef1ef21fbe90704286c8d0 (patch)
tree2b21e360ffc772b8b8c7b40ab1665cf67ea49a8c /mm/highmem.c
parentafe8605ca45424629fdddfd85984b442c763dc47 (diff)
downloadlinux-d2c20e51e3966bc668ef1ef21fbe90704286c8d0.tar.xz
mm/highmem: remove deprecated kmap_atomic
kmap_atomic() is being deprecated in favor of kmap_local_page(). Replace the uses of kmap_atomic() within the highmem code. On profiling clear_huge_page() using ftrace an improvement of 62% was observed on the below setup. Setup:- Below data has been collected on Qualcomm's SM7250 SoC THP enabled (kernel v4.19.113) with only CPU-0(Cortex-A55) and CPU-7(Cortex-A76) switched on and set to max frequency, also DDR set to perf governor. FTRACE Data:- Base data:- Number of iterations: 48 Mean of allocation time: 349.5 us std deviation: 74.5 us v4 data:- Number of iterations: 48 Mean of allocation time: 131 us std deviation: 32.7 us The following simple userspace experiment to allocate 100MB(BUF_SZ) of pages and writing to it gave us a good insight, we observed an improvement of 42% in allocation and writing timings. ------------------------------------------------------------- Test code snippet ------------------------------------------------------------- clock_start(); buf = malloc(BUF_SZ); /* Allocate 100 MB of memory */ for(i=0; i < BUF_SZ_PAGES; i++) { *((int *)(buf + (i*PAGE_SIZE))) = 1; } clock_end(); ------------------------------------------------------------- Malloc test timings for 100MB anon allocation:- Base data:- Number of iterations: 100 Mean of allocation time: 31831 us std deviation: 4286 us v4 data:- Number of iterations: 100 Mean of allocation time: 18193 us std deviation: 4915 us [willy@infradead.org: fix zero_user_segments()] Link: https://lkml.kernel.org/r/YYVhHCJcm2DM2G9u@casper.infradead.org Link: https://lkml.kernel.org/r/20210204073255.20769-2-prathu.baronia@oneplus.com Signed-off-by: Ira Weiny <ira.weiny@intel.com> Signed-off-by: Prathu Baronia <prathu.baronia@oneplus.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Matthew Wilcox <willy@infradead.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Randy Dunlap <rdunlap@infradead.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'mm/highmem.c')
-rw-r--r--mm/highmem.c6
1 files changed, 3 insertions, 3 deletions
diff --git a/mm/highmem.c b/mm/highmem.c
index 4212ad0e4a19..eb3b8c288de4 100644
--- a/mm/highmem.c
+++ b/mm/highmem.c
@@ -383,7 +383,7 @@ void zero_user_segments(struct page *page, unsigned start1, unsigned end1,
unsigned this_end = min_t(unsigned, end1, PAGE_SIZE);
if (end1 > start1) {
- kaddr = kmap_atomic(page + i);
+ kaddr = kmap_local_page(page + i);
memset(kaddr + start1, 0, this_end - start1);
}
end1 -= this_end;
@@ -398,7 +398,7 @@ void zero_user_segments(struct page *page, unsigned start1, unsigned end1,
if (end2 > start2) {
if (!kaddr)
- kaddr = kmap_atomic(page + i);
+ kaddr = kmap_local_page(page + i);
memset(kaddr + start2, 0, this_end - start2);
}
end2 -= this_end;
@@ -406,7 +406,7 @@ void zero_user_segments(struct page *page, unsigned start1, unsigned end1,
}
if (kaddr) {
- kunmap_atomic(kaddr);
+ kunmap_local(kaddr);
flush_dcache_page(page + i);
}